More Outdoor Time at School May Help Prevent Myopia in Children

(HealthDay News) — The addition of 40 minutes of outdoor activity at school for 6-year-old children in China resulted in a reduced incidence rate of myopia over the following three years. The research has been published in the Sept. 15 issue of JAMA.

Mingguang He, M.D., Ph.D., of Sun Yat-sen University in China, and colleagues randomly assigned children in grades one through 12 to an additional 40-minute class of outdoor activities (952 children; intervention schools), or the usual pattern of activity (951 children; control schools) for each school day. Parents of children at the intervention schools were encouraged to involve their children in outdoor activities after school hours.

The researchers found that the cumulative incidence rate of myopia at three years was lower in the intervention group (30.4 percent) than in the control group (39.5 percent; 95 percent confidence interval [CI], −14.1 to −4.1 percent; P < 0.001). The three-year change in spherical equivalent refraction also was different for the intervention group (−1.42 D) than the control group (−1.59 D; 95 percent CI, 0.01 to 0.33 D; P = 0.04). Elongation of axial length did not differ significantly between the groups (0.95 versus 0.98 mm; 95 percent CI, −0.07 to 0.003 mm; P = 0.07).

"Establishing the long-term effect of additional outdoor activities on the development and progression of myopia is particularly important because the intervention is essentially free and may have other health benefits," writes the author of an accompanying editorial.